docs: def get_value_format(value_format: Union[Callable, str] = str) -> Callable[[float], str]:
      """Create a formatting function from a generic value_format argument.
      """
      if value_format is None:
          value_format = ""
      if isinstance(value_format, str):
          format_str = "{0:" + value_format + "}"
  
          def value_format(x): return format_str.format(x)
  
      return value_format